Cage for medical balloon

ABSTRACT

A cage can be positioned around a medical balloon, such as an angioplasty balloon, to assist in a medical procedure. The cage can include a plurality of strips, each extending between a set of rings including first and second rings. As the balloon expands, the first and second rings move closer together and allow the strips to expand outward. The cage may have wedge dissectors on the strips.

CROSS-REFERENCE TO RELATED APPLICATIONS

Any and all applications for which a foreign or domestic priority claimis identified in the Application Data Sheet as filed with the presentapplication are hereby incorporated by reference under 37 CFR 1.57.

BACKGROUND OF THE INVENTION Field of the Invention

Certain embodiments disclosed herein relate generally to a cage for usewith a medical balloon, such as an angioplasty balloon. Methods ofmanufacturing the cage and treatment methods involving the cage are alsodisclosed.

Description of the Related Art

Atherosclerotic occlusive disease is the primary cause of stroke, heartattack, limb loss, and death in the United States and the industrializedworld. Atherosclerotic plaque forms a hard layer along the wall of anartery and is comprised of calcium, cholesterol, compacted thrombus andcellular debris. As the atherosclerotic disease progresses, the bloodsupply intended to pass through a specific blood vessel is diminished oreven prevented by the occlusive process. One of the most widely utilizedmethods of treating clinically significant atherosclerotic plaque isballoon angioplasty.

Balloon angioplasty is a method of opening blocked or narrowed bloodvessels in the body. The balloon angioplasty catheter is placed into theartery from a remote access site that is created either percutaneouslyor through open exposure of the artery. The catheter is passed along theinside of the blood vessel over a wire that guides the way of thecatheter. The portion of the catheter with the balloon attached isplaced at the location of the atherosclerotic plaque that requirestreatment. The balloon is generally inflated to a size that isconsistent with the original diameter of the artery prior to developingocclusive disease.

When the balloon is inflated, the plaque is stretched, compressed,fractured, or broken, depending on its composition, location, and theamount of pressure exerted by the balloon. The plaque is heterogeneousand may be soft in some areas or hard in others causing unpredictablecleavage planes to form under standard balloon angioplasty. Balloonangioplasty can cause plaque disruption and sometimes even arterialinjury at the angioplasty site.

SUMMARY OF THE INVENTION

There is a continuing need to improve the methods for treating occlusivedisease, including balloon angioplasty and other related treatmentsystems. In some embodiments a cage can be positioned around a medicalballoon, such as an angioplasty balloon, to assist in a medicalprocedure. The cage can include at least first and second rings and aplurality of strips. Each strip can extend longitudinally between thefirst and second rings. Moving the cage to an expanded position can movethe first and second rings closer together while expanding the strips.In some examples, the cage may further include spikes on the strips thatcan be used as wedge dissectors to dissect plaque in a vessel, amongother things.

The cage can be assembled and/or manufactured in many ways, including,in some examples, an extrusion process, material removal from a tube, orby splitting a wire to form the strips.

The cage can assist a medical procedure in many ways. For example, thecage may cover a drug coating on the balloon pre-deployment. In somevariants, when the cage is expanded, the cage may allow access to thedrug coating on the surface of the balloon. In this way, the cage canprevent or reduce the chances that the drug will become diluted duringdelivery or will treat areas of the body not intended for treatment.

As another example, the cage can prevent or reduce dog boning of theballoon by increasing the resistance to expansion of the combinedballoon and cage at the ends of the cage as compared to the center ofthe cage.

In some embodiments, a balloon catheter can comprise an elongate member,a balloon, and a cage. The elongate member can have an inner lumen, theelongate member defining a longitudinal axis. The balloon can beconnected to the elongate member at a distal end of the elongate member.The cage can be for positioning about the balloon. The cage can comprisea plurality of strips and a plurality of rings. The plurality of ringscan be configured to secure the plurality of strips to the ballooncatheter. Each strip of the plurality of strips can have a first ring ofthe plurality of rings at a distal end, a second ring of the pluralityof rings at a proximal end. At least a portion of the strip between thedistal and proximal ends remains uncovered by and/or unconnected to anyring. The balloon and cage are configured to have an initial state andan expanded state, the plurality of strips configured to move with theballoon as it moves toward the expanded state.

According to some embodiments of the balloon catheter, at least some ofthe rings of the plurality of rings comprise a heat shrink material.Further each strip of the plurality of strips can include a plurality ofwedge dissectors spaced along a surface of the strip, each stripextending longitudinally along an outer surface of the balloon. Theplurality of rings can secure the plurality of strips to distal andproximal ends of the balloon. At least some of the strips of theplurality of strips can be secured with rings at intermediate points ofthe balloon. The strip may be secured at intermediate points and/or atthe ends.

In some embodiments, at least some of the rings of the plurality ofrings comprise a part ring having a top layer of heat sink material anda bottom layer, an end of a strip of the plurality of strips sandwichedbetween the top layer and the bottom layer. Some embodiments can includehooks on the strips, grooves on the strips or rings, springs, and otherfeatures.

A method of retrofitting a balloon catheter with a cage can comprise anyof the below steps. Positioning a plurality of strips around an inflatedballoon of a balloon catheter, the strips being positioned equallyspaced around the inflated balloon. Advancing rings of heat shrinkmaterial over the balloon so that each end of the strips of theplurality of strips is covered by a ring heat shrink material. Heatingthe rings of heat shrink material to shrink the rings of heat shrinkmaterial to thereby secure the plurality of strips to the balloon, atleast a portion of each strip of the plurality of strip between distaland proximal ends of the strip remaining uncovered by and/or unconnectedto any ring of heat shrink material.

A method may further include positioning positioning the strips toextend primarily longitudinally, and/or positioning the strips seriallyin rows around the balloon with 4 rows, each having between 2-6 stripsper row. The strips can be attached either permanently or temporarily tothe balloon with an adhesive.

Advancing rings of heat shrink material over the balloon further maycomprise covering a distal end of distal-most strips of the plurality ofstrips with a single ring of heat shrink material. Further, advancingrings of heat shrink material may include covering a proximal end ofproximal-most strips of the plurality of strips with a single ring ofheat shrink material. Still further, it can include covering a proximalend of distal-most strips of the plurality of strips and a distal end ofproximal-most strips with a single ring of heat shrink material.

In some embodiments, a cage can be positioned around an angioplastyballoon. The cage can include first and second rings and a plurality ofstrips. Each strip of the plurality of strips can extend longitudinallybetween the first and second rings. The cage can have a pre-expansionposition and an expanded position, wherein moving to the expandedposition moves the first and second rings closer together whileexpanding the strips.

A method of making a cage for an angioplasty balloon can compriseextruding a plastic tube with a plurality of spaced apart splinespositioned longitudinally along the tube; cutting at least one of thesplines of the plurality of splines to form a plurality of spikespositioned circumferentially around the tube; and cutting the tube toform a plurality of longitudinally extending strips, each stripincluding at least one spike of the plurality of spikes.

A method of making a cage for an angioplasty balloon can comprisesplitting a wire into a plurality of longitudinally extending strips;cutting at least two longitudinally extending strips of the plurality oflongitudinally extending strips to form a plurality of spikes spacedapart along the longitudinally extending strip; and connecting the atleast two longitudinally extending strips to a first ring and a secondring such that each strip of the plurality of longitudinally extendingstrips extends between the first and second rings.

A method of protecting an angioplasty balloon with a drug coating cancomprise providing an angioplasty balloon with a drug coating; providinga cage having a pre-expansion position and an expanded position, thecage comprising: first and second rings; and a plurality of strips, eachstrip of the plurality of strips extending between the first and secondrings; wherein the cage is positioned over the angioplasty balloon suchthat in the pre-expansion position the cage covers the angioplastyballoon radially such that none, or substantially none, of the surfaceof the angioplasty balloon with the drug coating is exposed, and movingto the expanded position moves the first and second rings closertogether while expanding the strips and exposing the angioplasty balloonsurface.

A method of treating a diseased blood vessel can comprise advancing anangioplasty balloon, optionally with a drug coating, to a treatment sitein a diseased blood vessel, the angioplasty balloon having a cagepositioned over the angioplasty balloon, the cage having a pre-expansionposition and an expanded position, the cage comprising: first and secondrings; and a plurality of strips, each strip of the plurality of stripsextending between the first and second rings; expanding the angioplastyballoon at the treatment site, where expanding the angioplasty balloonfurther comprises moving the first and second rings closer togetherwhile expanding the strips, the cage preventing or reducing dog boningof the angioplasty balloon by increasing the resistance to expansion ofthe combined angioplasty balloon and cage at the ends of the cage ascompared to the center of the cage.

In some embodiments, a cage for positioning about an angioplasty ballooncan include a plurality of rings and a plurality of strips. Theplurality of rings can be non-expandable. At least one of the pluralityof rings can be configured to be disposed about a first end of anangioplasty balloon, and at least one of the plurality of rings can beconfigured to be disposed about a second end of the angioplasty balloon.Each of the plurality of strips can include a plurality of protrusionspositioned on the surface of each of the plurality of strips. Each ofthe plurality of rings can be configured to attach to each end of theplurality of strips. The plurality of strips can be attached to theplurality of rings through a coupling. In some embodiments, the cage canhave a first length and a second length. The second length is shorterthan the first length, and the plurality of rings are closer inproximity with each other such that each of the plurality of stripsbends away from each of the plurality of strips.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other features, aspects and advantages are described belowwith reference to the drawings, which are intended to illustrate but notto limit the invention. In the drawings, like reference charactersdenote corresponding features consistently throughout similarembodiments.

FIG. 1A illustrates a cage positioned on an angioplasty balloon in anexpanded position.

FIG. 1B shows an exploded view of an angioplasty balloon that can bepositioned within a cage, both being shown in a pre-expanded position.

FIG. 2 shows a schematic representation of a cage laid flat showing bothlong and short slits.

FIG. 3 shows an angioplasty balloon within a vessel at a treatment sitethat is experiencing dog boning.

FIG. 4A shows an unfinished cage during manufacturing being cut from atube.

FIG. 4B is a cross-section of the unfinished cage of FIG. 4A taken alongline B-B.

FIG. 4C shows the cross-section of FIG. 4B after an additionalmanufacturing step.

FIG. 4D illustrates a cross-section of another embodiment with a largerinterior lumen.

FIG. 4E shows a detail view of a portion of another embodiment of cage.

FIG. 5A shows another embodiment of an unfinished cage duringmanufacturing.

FIG. 5B shows a cross-section of the unfinished cage of FIG. 5A takenalong line B-B.

FIG. 6A shows a wire cut to form strips and wedge dissectors for anembodiment of a cage.

FIG. 6B shows a section of the cut wire of FIG. 6A.

FIG. 7 shows a schematic view of a plurality of strips that areconnected by two rings to form a cage.

FIG. 8 illustrates a two-part ring that can be used to capture strips toform part of a cage.

FIG. 9A is another embodiment of cage with a conical ring.

FIG. 9B is a perspective view of a ring with a tapered outer diameterwherein the ring includes a screw-like feature on its outer surface.

FIG. 10 shows the end of a strip configured to accommodate and besecured by a multi-layer ring to form an end of the cage.

FIG. 11 illustrates another embodiment of the end of a strip configuredto accommodate and be secured by a multi-layer ring to form an end ofthe cage.

FIG. 12 is a perspective view of a ring.

FIG. 13A shows a strip with a hook feature and ring.

FIG. 13B is an end view of strip with a ridged hook feature.

FIG. 13C shows a perspective view of a portion of a cage.

FIG. 13D illustrates a view of a conical distal ring retaining aplurality of strips.

FIGS. 13E-F show a view of one end of a balloon with a cage disposedabout the balloon and the forces applied to the balloon during inflationand deflation.

FIG. 14A illustrates a side view of an embodiment of a cage havingstrips with hooks that can attach to the inside of a balloon neck.

FIG. 14B shows an end view of a cage attached to a balloon asillustrated in FIG. 14A.

FIG. 14C is a cross sectional schematic view of the strip with hooklocked into the balloon neck.

FIG. 14D is an alternative embodiment of the end of a strip with amulti-layer ring to form an end of the cage.

FIGS. 14E shows an embodiment of a strip retained by a plurality ofrings with the wedge dissectors protruding from the plurality of rings.

FIG. 15A illustrates a partial view of an embodiment of an angioplastyballoon with an embodiment of a strip bound to the angioplasty balloonwith a plurality of ringed material to form a cage.

FIG. 15B is an angioplasty balloon with a cage having a plurality ofsegmented strips that are bound to the surface of the balloon by aplurality of rings.

FIG. 15C shows an example of the placement of the segmented strips onthe surface of the balloon.

FIG. 15D is another example of the placement of a plurality of segmentedstrips onto the surface of an angioplasty balloon.

FIG. 15E illustrates an example of a plurality of segmented strips boundto the surface of a balloon by a plurality of rings.

FIGS. 16A-C show a plurality of embodiments of strips secured by a ring.

FIG. 17 illustrates a schematic view showing a detail of an embodimentof a cage with a spring.

FIG. 18 illustrates various an embodiments of a cage utilizing aspectsof the spring detail of FIG. 18.

FIG. 19 shows a portion of a cage including a spring strip and spikeconfiguration.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

FIGS. 1A and 1B illustrate an embodiment of a cage 10 positioned on anangioplasty balloon 20. FIG. 1A shows an expanded position and FIG. 1Bshows how the angioplasty balloon can be advanced into the cage. Thecage 10 is described herein primarily with respect to an angioplastyballoon 20 and an angioplasty procedure. It is to be understood that thecage 10 can be used with other types of medical balloons and in otherprocedures.

The cage 10 can include a first ring 12 and second ring 14, and aplurality of strips 16. Each strip can extend longitudinally between thefirst ring 12 and the second ring 14. The strips and rings can be madeof a monolithic part formed from a single piece of material. Thus, thefirst and second rings can be the ends of a cut tube, for example. Thestrips and rings can also be made of separate materials and be connectedtogether. As shown the illustrated cage of FIGS. 1A and 1B has fivestrips 16, though other numbers of strips can be used such as 2, 3, 4,5, 6, 7, 8, 9, 10, etc.

FIG. 2 shows a plan view of a cut tube embodiment of cage, though someembodiments of cage can alternatively be made of a single flat piece ofmaterial. The material can be elastic or semi-elastic and made from apolymer, copolymer, a metal, alloy or combination of these. The stripsare typically designed to enable the balloon 20 to be inflated multipletimes. As well, the strips 16 can be configured such that the cage 10can apply forces both longitudinally and axially or in orientations thatenable the strips 16 to return to this original position.

In some embodiments the cage 10 is prefabricated, packaged, andsterilized separately from the balloon 20, allowing the physician toposition the cage 10 around a medical balloon 20, such as an angioplastyballoon, to assist in a medical procedure at the time of the procedure.FIG. 1B shows the balloon 20 in a folded state prior to deployment andprior to placement within the cage 10. The folded balloon 20 can beadvanced into the cage 10 without requiring expansion or change in shapeof the cage 10. The cage 10 can completely surround and enclose theballoon 20 prior to balloon deployment or expansion. The cage 10 in thepre-expanded state can be longer than the balloon 20. This can allow formovement of one or both ends of the cage 10 towards each other while thedevice (e.g. balloon 20) expands. The cage 10 can be free floating overthe balloon 20. One or both ends 12, 14 of the cage 10 may be fixed tothe balloon 20 or another part of the delivery device. In someembodiments the cage 10 is not attached to any portion of the balloon 20that expands. This can prevent the cage 10 from interfering with theballoon 20 as it expands.

In some examples, a cage 10 can be used with an angioplasty balloon 20with a drug coating to can protect the drug coating. The cage 10 canprevent or reduce the premature exposure of the drug to the bloodvessel. As will be understood with reference to FIG. 1B, the cage 10 canbe positioned over a drug coated angioplasty balloon 20 in thepre-expansion state to prevent premature exposure of the drug to theblood vessel. The cage 10 can cover the balloon 20 radially such that aminimal amount, or substantially none, of the surface of the angioplastyballoon 20 with the drug coating is exposed. The balloon 20 and cage 10can be advanced to a treatment location in this configuration. Thoughnot shown, the system may be advanced over a guidewire within thevasculature.

As illustrated in FIG. 1A, the cage 10 can be moved to an expandedposition. In the expanded position the first 12 and second rings 14 arecloser together and the strips are expanded thereby exposing theangioplasty balloon surface. In this position, the drug can be placedinto contact with diseased tissue in the blood vessel.

In currently available systems, it is generally difficult to predict howmuch drug will reach the diseased tissue. There are many factors thatlimit the ability to accurately predict how much drug will betransferred to the diseased tissue. For example, blood flow can dilutethe drug on the balloon 20 as it is advanced to the treatment site.Furthermore, navigating the device through the blood vessel can causethe balloon 20 to rub against the endoluminal surface thereby removingsome of the drug as the balloon 20 is being advanced to the treatmentlocation. Therefore, in some examples, the cage 10 can offer a physicalbarrier to protect the drug covering of the balloon 20 duringadvancement to the treatment location. In this way the cage 10 can beused such that balloon 20 and drug covering are exposed to blood flow ina vessel only during expansion of the balloon 20 as the space betweenthe strips increases. In this way, the cage 10 can prevent or reduce thechances that the drug will become diluted or that the drug will treatareas of the body that are not meant for treatment. In some variants,this can allow for more controlled delivery of the drug with a reductionin the amount of drug necessary to be coated on the balloon 20.

In some embodiments, the folded balloon 20 can be positioned entirelywithin the cage 10. As is illustrated in FIG. 1A, the cage 10 can haveslits between each of the strips 16. In some variants, the slits can beformed by cutting between each of the strips 16 to separate them from asingle piece of material. In other embodiments, the slits are reallyjust the space between adjacent strips. The space between strips can bea minuscule amount, such as would formed by a laser cut, or much larger,such as equal to or greater than a width of the strip itself. Dependingon the size of the slits, the exposed surface of the balloon 20 in thepre-expansion position is not more than 50% and can be as low as 25%,10%, 5%, 1%, or less.

As has been described previously, expansion of the balloon 20 moves thefirst 12 and second rings 14 closer together while moving the strips 16further apart radially. With the strips 16 in an expanded position, theballoon 20 is more exposed to and can interact with the vessel wall. Inthe expanded position, the balloon 20 can deliver a drug, stem cells, orother treatment to the vessel wall or to a diseased area of the vesselwall. When the balloon 20 is fully expanded, the exposed surface of theballoon 20 not covered by the strips 16 can be between 65% and 99%, 75%and 99%, more commonly 80% and 99%, or most commonly 90% and 99%, amongother ranges.

Drug delivery using the cage 10 can be employed before, during, or afteran angioplasty procedure. At the same time, it is not required that thecage cover the entire balloon, or be used to control or assist with drugdelivery.

In some embodiments, a cage 10 can be used to prevent or reduce dogboning of the balloon 20 in an angioplasty procedure. This may be inaddition to, or instead of assisting with drug delivery. FIG. 3 shows anangioplasty balloon 20 within a blood vessel 2 at a treatment site. Asillustrated, the angioplasty balloon 20 is experiencing dog boning as itis expanding. The plaque buildup 4 resists expansion of the balloon 20,forcing both ends of the balloon 20 to expand first, rather thanfocusing the expansion energy in the center of the balloon 20 at theplaque 4 where it is needed most.

To prevent dog boning, the cage 10 as shown in FIG. 1A, can constrainthe balloon 20 upon expansion to encourage the middle of balloon 20 toexpand first. This is because the middle area of the cage 10 can bedesigned to have the least resistance to expansion, being farthest awayfrom the ends where the strips are confined by rings. This can preventor reduce dog boning of the balloon 20 independent of the diseasemorphology or arterial topography the balloon 20 is expanding within.

Dog boning usually occurs where a balloon 20 expands in a vessel withplaque where the plaque resists expansion, forcing the ends of theballoon 20 to expand first (due to lack of resistance) such that theballoon 20 takes the shape of a dog bone. By enveloping a balloon 20with a cage 10 and configuring the rings to display different expansionresistance, the ends of the balloon 20 can have the highest resistanceand the center of the balloon 20 have the lowest resistance. Therefore,the cage 10 can help control and limit expansion of the balloon 20, asthe balloon 20 will tend to expand more readily in the center which istypically the area of disease.

The pattern and orientation of the strips 16 can influence expansion anddog boning. Returning to FIG. 2, the short slits 22 positioned in thecenter of the strips 16 can reduce rigidity in the center of each of thestrips 16. This can help reduce the likelihood of dog boning by furtherreducing resistance to expansion in the center of the cage 10.

The cage may further include spikes or wedge dissectors on the strips.The spikes can be used as a vessel preparation tool before a secondarytreatment, or during a primary treatment. For example, the spikes canassist with cutting and/or perforating plaque before or during anangioplasty procedure. This may be in addition to, or instead ofassisting with drug delivery and/or preventing dog boning. It will beunderstood that any of the embodiments described herein can provide anyof these benefits and/or be used in any of these procedures, as well asthe other benefits and procedures described herein.

Spikes can be positioned on the strips in any number of differentorientations and configurations as will be described further below. Thespikes can be any of the spikes discussed in U.S. Pat. No. 8,323,243,issued Dec. 4, 2012 (Atty. Docket No. INNV.014A), entitled “DEVICE ANDMETHOD FOR OPENING BLOOD VESSELS BY PRE-ANGIOPLASTY SERRATION ANDDILATATION OF ATHEROSCLEROTIC PLAQUE,” incorporated by reference hereinand included in the attached Appendix. The spikes and cage can also beused in accordance with the plaque serration methods and other methodsalso described therein.

The cage 10 can be made in many ways. For example, an extrusion processmay be used, a tube may be cut, and/or a wire split as will be describedin more detail below. Beginning with FIGS. 4A-5B, various embodiments ofcages will be described. FIGS. 4A and 5A show embodiments of cages 10during the manufacturing process. The cages 10 are each in the form of atube with a plurality of splines 24 spaced apart on the tube. In someembodiments, the tube can be pre-formed and then machined to theillustrated shape. The tube can be made of metal or plastic among othermaterials. In other embodiments, the tube is extruded to form theillustrated shape. For example, a method of making the tube can includeextruding a plastic tube with a plurality of spaced apart splines 24positioned longitudinally along the tube. Cross-sections of the cagesare shown in FIGS. 4B-D and 5A.

After forming the tube with the splines 24, material from the tube canbe removed to form the slits and strips 16. Either as part of removalprocess, or before creating the slits, the splines may be shaped to formdifferent shaped spikes or wedge dissectors 26. For example, the splines24 illustrated in FIG. 4B can be machined to form the sharp wedgedissectors 26 as shown in FIGS. 4C and 4D. In some embodiments, thesplines 24 can be manufactured with an additive process and shapedinitially like the illustrated wedge dissectors 26 without requiringadditional machining or other work.

Looking now to FIG. 4E, an enlarged detail view of a portion of a cageis shown. In this embodiment, the strip 16 has been formed with aplurality of spikes or wedge dissectors 26. In some embodiments, fromthe base of the unfinished cage of FIGS. 4A and 4B, a slit can be cut inthe tube to form adjacent strips. The wedge dissectors 26 can be shapedlike a tent or axe head with an elongated tip and base, both of whichextend longitudinally, along the longitudinal axis of the tube. Thewedge dissectors 26 can assist with cutting and/or perforating plaquebefore or during an angioplasty procedure. The space between the wedgedissectors 26 can be machined or otherwise formed to remove material andincrease the flexibility of the strip. The space between the wedgedissectors 26 is shown as being twice the length of the wedge dissector26, though other spacing can also be used. Typically spacing length canbe 4:1 to 3:1 space to length and more commonly 3:1 to 1:1 space tolength.

Turning to manufacturing of the splines, in some embodiments, thesplines 26 are fabricated from a tube of material, where the cage 10 isa plastic extruded tube with splines that are cut, ground, electricaldischarge machined, or molded to form the wedge dissectors 26. The tubecan be manufactured with slits along its length. In some examples, theends of the tube remain intact in order to forming rings. In somevariants, the strips 16 are spaced apart with some or all the strips 16having spikes or wedge dissectors 26. As will be understood from theabove discussion, in the embodiments shown in FIGS. 4A-5B five slitswould be made to form outward points.

In some embodiments, a method of making a cage 10 for an angioplastyballoon 20 can comprise first extruding a plastic tube with a pluralityof spaced apart splines positioned longitudinally along the tube. Insome examples, the method can then include cutting at least one of thesplines of the plurality of splines to form a plurality of spikes orwedge dissectors 26 positioned circumferentially around the tube. Insome variants, the method can further include cutting the tube to form aplurality of longitudinally extending strips 16, each strip including atleast one spike of the plurality of wedge dissectors 26.

Looking now to FIGS. 6A-6B, another method of manufacturing a cage 10will be described. A wire 28 can be split or cut to form three or morestrips 16 that can be used as part of forming a cage 10. In someexamples, the wire 28 is constructed of an alloy, or polymeric material.Any number of different manufacturing methods can be used includinglaser cutting and electrical discharge machining. In some variants, thewire 28 can be divided into sections, such as four quarters. In someembodiments, square or other shaped holes 30 can be cut into the wire 28to form spaces between the wedge dissectors 26. Each of the sections ofwire can then be separated to form the strips 16 of the cage 10. A cage10 can be assembled with a plurality of rings and include any number ofstrips 16. In some examples, a cage 10 can be assembled from 1, 2, 3, 4,5, 6, 7, 8 or more strips 16.

Systems and Methods for Connecting Individual Strips

Strips 16 can be attached in many ways to form the cage 10. In addition,to forming the strips from a wire, they can also be extruded and/orformed from a flat piece of material and/or a tube. For example, it willbe understood that the embodiments described with reference to FIGS. 2,4A-5B can be modified to provide individual strips that can then beconnected to form a cage.

In some embodiments, strips can be connected with two or more rings 12,14 to form a cage 10. For instance, the individual strips of the cage 10may be bonded to rings on either end. As illustrated in FIG. 7, eachindividual strip 16 is secured on either end by rings 12, 14. Inconstructing the cage 10, the strips 16 can be attached to the rings 12,14 first before positioning around a balloon, or the cage can beassembled around a balloon. For example, one or more strips can beplaced onto the surface of the balloon 20 before connecting to therings. The cage 10 may be permanently fixed to one or both ends of theballoon 20 or to the balloon catheter. In some embodiments, the rings12, 14 can hold the strips against a portion of the balloon or theballoon catheter. The strips 16 can also help to keep the balloon 20 ina compressed state prior to deployment and can assist in deflating theballoon after expansion.

The rings 12, 14 are typically circular bands, though they can be a bandof any number of shapes including oval, square, elliptical, rectangular,etc. The rings can also be capable of producing a binding and/orrestraining force. The rings 12, 14 can be any number of differentmaterials including one or more of a metal, polymer, copolymer,elastomer, thermoplastic elastomer, glue, or hydrogel. The rings can berigid or flexible.

In some examples, the rings 12, 14 can be composed of a heat shrinkmaterial or a material with elastic properties that binds, captures, orrestrains the plurality of strips 16 and prevents or limits the strips16 from moving, sliding, tilting or twisting at any point along thelength of the strips but especially at either end of the balloon 20.When the rings are elastic, super elastic, or thermally active, therings can be placed about the strips and allowed to shrink onto thestrips such that the strips 16 are retained against the outer diameterof the balloon 20. Preferably, the rings and strips are positionedaround a balloon in a fully expanded state and then heat is applied tothe heat shrink type rings. In other embodiments, the heat shrink typesrings are applied with the balloon in a deflated state.

As discussed with respect to FIGS. 1A and 1B the cage can be performedand slid onto the balloon. But, in some embodiments, assembling the cagearound the balloon can allow for a smaller cage design. In retrofittingthe balloon 20, the rings can be advanced onto the balloon catheter fromeither side which may allow for a smaller ring inner dimension ascompared to a cage with one ring that is advanced over a balloon.

The rings 12, 14 of the cage 10 can be configured to accommodate theballoon 20 as it transitions from a deflated to an inflated shape. Notunlike the configuration of the cage with balloon illustrated in FIG.1B, the strips 16 of the cage 10 can be in contact with the balloon 20when the balloon 20 is in a deflated configuration. As the balloon 20inflates, each strip 16 bows in a concave orientation with the balloon20 (FIG. 1A). In some examples, the strips 16 are free-floating and notbound to the balloon surface.

As the balloon 20 begins deflating, the material properties of thestrips 16 can allow it to begin to return to their original position.This may be a completely flat position. As the strips 16 return to theiroriginal position, this can provide an additional force to assist thedeflation of the balloon 20. As the strips move from the concaveposition to a flat linear position, the strips 16 move from an expandedlength (“L_(e)”) to a deflated length (“L_(d)”) where L_(d) is longerthan L_(e). The straightening of the strips 16 from L_(e) to L_(d) inthe axial direction elongates the balloon 20 and assists in morecomplete balloon 20 deflation.

The rings 12, 14 can come in a variety of shapes and sizes that cansecure the plurality of strips 16. The following discussion of certainillustrated embodiments, are but a few such examples.

The rings 12, 14 can connect to the strips 16 in a number of differentways. The rings can be mechanically attached to the strips 16 through afriction fit for example, or can be connected with an ultrasonic weld,adhesive, etc. Turning to FIG. 8, each ring 12, 14 can be a two-partring that can connect to one or more strips 16 of the cage 10 byrotating the rings in opposite directions (e.g. clockwise andcounterclockwise). The rings 12, 14 can include holes 32, through whichthe strips 16 can be advanced to connect to the ring. In particular, theasymmetrical shape of the holes 32 can be configured to accommodate astrip 16 with periodically spaced wedge dissectors 26 such as thatillustrated in FIG. 6B.

As illustrated, the holes 32 can have a narrowed portion 33 and a widerportion 34. The wider portion 34 can be configured to accommodate thewedge dissector 26 while the narrowed portion 33 can be configured toaccommodate the width of the strip 16 (i.e. the space between wedgedissectors). The strips 16 can be advanced through the holes 32 byfitting a wedge dissector 26 through the wider portion 34. In someexamples, the strip 16 can then be secured by turning the rings 12, 14such that the strip 16 is moved into the narrowed portion 33. This cansecure the strips 16 to the rings 12, 14 as the wedge dissector 26cannot move past the narrowed portion 33. As described above, both rings12, 14 can be present at either end of the cage 10. Additionally, asillustrated in FIG. 8, because the holes 32 of the ring 12 and the holes32 of the ring 14 are opposed, by rotating the two parts of the ring inopposite directions, this further prevents movement of the strips 16.

The strips 16 can be secured by rings 12, 14 that are formed from avariety of shapes. For example, FIG. 9A illustrates an embodiment of thecage 10 where the strips 16 are secured with a conical ring 12 at thedistal end. The conical end can be the distal end of the ballooncatheter and can provide an atraumatic end of the device.

Similarly, FIG. 9B shows a ring 12 with a tapered outer diameter with ascrew feature 101 on its outer surface. This screw feature 101 canprovide either a negative or positive impression about the outer surfaceof the distal ring.

The ring 12 illustrated in FIG. 9B can serve a treatment purpose aswell. In some examples, the tapered and screw features on the ring canassist the balloon 20 in navigating and entering a narrow lesion. Thecoiled outer surface 101 can be configured to provide a gripping ortunneling mechanism. This feature can allow the ring to aid the operatorin navigating through occluded lesions (either totally or partially) andenable passage of the balloon 20 therein. The negative or positiveimpression 101 can be circumferential or patterned like a cork screw. Insome embodiments, the negative or positive impression 101 can be macroin scale or have micro features that offer an enhanced surface to enablepassage through a narrowing in a vessel. In some examples, the functionof the outer surface 101 of the ring can be described as acting like alubricant although the feature is mechanical in nature. This functioncan be further enhanced with hydrophilic, hydrophobic coating. Thesurface texture can also be modified to aid in passages with lesspenetration energy. In some embodiments, this can be accomplished byadding micro scales (as seen in porcupine quills) or enhanced surfaceroughness (as used in nature by mosquitos).

The ring 12 illustrated in FIG. 9B can be secured to strips 16 that aredisposed about the surface of the balloon circumferentially in a helicalfashion. In contrast to the linear strips 16 illustrated in FIG. 9A, thestrips 16 attached to the tapered ring 12 can be wound around theballoon. A tapered or untampered ring 14 can be used at the proximal endof the balloon. In some examples, the configuration of the attachedstrips 16 can follow the same pattern as the negative or positiveimpression 101 on the ring 12.

Turning now to FIGS. 10-11, multiple layer rings will be discussed. Aring with multiple layers can be used to hold the strips between thelayers. The ring can have at least a base layer 122 and a top layer 121.As seen in FIGS. 10-11, the ring 12, 14 can have a non-compressiblebottom layer 122 and a compressible, thermally or electrostaticallycompressible layer 121. The top layer 121 can be configured of acompressible material while the base layer 122 can be configured of anon-compressible material and the strips 16 can be captured betweenthem. In some examples, the top layer or the top and base layers can bemade from a heat shrink material. In some embodiments, the ring 12, 14can be formed from lengths of materials that are wound around themselvesto form a layer of ring.

The rings can be made of a layer of composite materials where the baselayer 122 is less compressible or elastic than the top layer 121. Energycan be added to the top layer 121 to produce a reduction in the toplayer's diameter until the top layer compresses and captures the stripsbetween the base layer 122. For example, the top layer 121 can be a heatshrink material. In this way, the top layer 121, base layer 122 andstrips 16 can form a cage 10 as seen in FIGS. 10 and 11. In someembodiments, the strips can be attached to the balloon and/or ballooncatheter with the rings that are made of a single layer of heat shrinkmaterial positioned over the strips similar to just the top layer.

The strips or rings can include indentations to facilitate attachment tothe other. The strip 16 can include an indentation 171 on either side ofthe strip 16 (as illustrated in FIG. 10) or an indentation 171 on onesurface of the strip 16 that can form a groove (as illustrated in FIG.11). Though in FIG. 11, the top layer 121 is shown as a heat shrinkmaterial, it will be understood that in other embodiments a rigid ringcould be press fit into the indentation 171. Such a rigid ring could bepart of a single or multiple layer ring, thus there may or may not be acorresponding base layer 122.

FIG. 12, illustrates another embodiment of the ring 12, 14. Here, thering 12, 14 can include a plurality of indentations or grooves 17. Thegrooves 17 can have a width that can accommodate the width of the distalend of strip 16. An end of a strip can be attached to the ring 12, 14 inthe grooves 17 through the use of adhesive, mechanical coupling,wrapping heat shrink material around the ring, etc. In some embodiments,the strip 16 of FIG. 11 can be placed in the ring 12, 14 of FIG. 12 sothat the indentations are engaged with each other.

FIGS. 13A-C illustrate examples of a strip 16 that includes ansecurement feature 181 that improves the hold of the strips 16 to therings 12, 14. In some variants, the securement feature 181 forms asection of the strip 16 with a higher surface roughness. This can be inthe form of the illustrated ridges or other teeth-like elements that aidin the imbedding of the strip 16 into or holding the strip on the ring.

When the ring 12, 14 is a polymeric material, the securement feature 181can be formed as narrow sections of the strip 16 at the ends (asillustrated in FIG. 13A-B), or placed strategically along the striplength (such as where three or more rings are used). The securementfeature 181 can be aligned with the rings 12, 14. During fabrication,the securement feature 181 can be pressed into the polymeric material asillustrated in FIG. 13A at a high temperature where the polymericmaterial is near or greater than the glass transition temperature of thematerial. In so doing the securement feature 181 can be used to engageor connect the strips 16 to the rings 12, 14 as illustrated in FIG. 13C.

In FIG. 13A the ring 12, 14 is shown to incorporate the securementfeature 181 into the body of the ring material. FIG. 13A shows the strip16 with a ridged hook feature 181 before it is pressed into the ringmaterial. FIG. 13B shows a perspective view of another embodiment ofsecurement feature 181. In some examples, the securement feature 181 canbe significantly longer than the ring 12, 14 is wide and be designed toprovide tension on the cage 10.

When the ring 12, 14 is made from an elastic material, such as rubber orpolymer, or metallic alloy or a design with elastic properties like aspring, the ring 12, 14 can be used to provide tension on the cage 10 toenable the cage 10 to return to the relaxed, deflated balloon 20position. Furthermore, the portion of the strips 16 without a wedgedissector is the thinnest and the most flexible. This can allow thestrip 16 to be the most flexible at the edge of the balloon 20 where theforces are the highest.

FIGS. 13D-F illustrate an example where the elastic material of a ringcan provide tension on a cage during expansion and to then assist indeflating the balloon as the tension is released. Turning first to FIG.13D, the cage 10 is disposed about the balloon 20. The cage 10 can becomposed of a plurality of strips 16 that are secured to the balloon byrings 12, 14. In some examples, the rings 12, 14 can be made from longelastic material that can aid in pulling the strips 16 down into alinear position such that the wedge dissectors are perpendicular to thesurface of the balloon 20. Callout “A” provides a schematic, see-throughview of the proximal end of ring 14. As shown, ring 14 is secured aboutthe outer catheter shaft 22 by an adhesive 23. As well, an innerguidewire shaft 21 can run concentric to the balloon 20. The guidewireshaft 21 can be secured with relationship to the catheter shaft 22. Forexample, the guidewire shaft 21 and the catheter shaft 22 can both beconnected to different ports on a hub, such as the illustratedbifurcated luer at the proximal end of the balloon catheter. The ballooncan be inflated by injecting a fluid into the catheter shaft. It will beunderstood that in some embodiments the catheter shaft 22 open directlyinside the balloon 20, rather than opening at the ring 14 as shown. Thering can be attached to the catheter shaft 22 and/or the balloon 20.

FIGS. 13E-F illustrate a balloon 20 and cage 10 as the balloon 20 isinflated and subsequently deflated. As noted above, in some examples,the elastic material of the rings 12, 14 can stretch to allow the cage10 to expand as the balloon 20 is inflated. In some embodiments such asthe shown in FIGS. 13E-F, the rings can be made of an elastic polymerand the strips can be made of metal or an inelastic polymer. As shown inFIG. 13E, as the balloon 20 is inflated, the strips 16 of the cage 10begin to move apart. In order to push each of the strips 16 outward,force is exerted radially outwards (as illustrated by the arrows) on theballoon 20—and by extension the cage 10—as the balloon 20 is inflated.As the balloon 20 expands, the rings 12, 14 are under tension and ableto stretch enough to allow the strips 16 to maintain alignment whileexpanding with the balloon 20.

This tension can also help the balloon 20 to deflate. During balloondeflation, as illustrated in FIG. 13F, the tension on the strips 16exerts a force radially inward as the strips 16 and the rings 12, 14tend to want to return to a relaxed state. This force pulls on thestrips 16 and allowing them to flatten, thereby providing a narrowedprofile for catheter retraction.

Looking now to FIGS. 14A-D another embodiment of strip 16 is shown withvarious types of rings. As illustrated in FIGS. 14A-B, in some examples,the ring can be fabricated from the lip on the neck of the balloon 20and the portion of the catheter body used to bond the catheter to theballoon 20. The catheter can provide a pathway for gas or liquidinflation of the balloon 20. Additional components such as an over moldor heat shrink can be added to the bond joint, as can additive glue orpolymeric material. In some examples, this can serve to prevent pressurefrom leaking out of the balloon 20 along the length of the strips 16forming the cage 10.

As illustrated in FIGS. 14A-D, a hook 161 at the strip end can enablethe strip to be easily aligned along the balloon surface and can aid inorienting the strip in a longitudinal orientation relative to the axisof the balloon 20. The hook 161 can be integrated into each end of thestrip 16. The hook 161 can be wrapped around the lip of the neck of theballoon 20 from the outer diameter (“OD”) of the balloon 20 neck aroundthe opening and into the neck where the end of the hook 161 rests withinthe inner diameter (“ID”) of the balloon 20 neck.

Both ends of the strip 16 can have a hook 161, or just one end can havethe hook. In addition, the ends can be attached to the balloon catheterin the same or in different ways. For example, heat shrink can bewrapped around the ends of the strips and balloon. In some embodiment,heat shrink is wrapped around one end and a rigid ring, such as thosediscussed with respect to FIGS. 8-12 can be used at the other end, whichmay also include a heat shrink layer.

The strip may or may not be attached to the balloon at other locations.As shown, the strip 16 can also have hinges or pre-bent regions thatcorrespond with the shape of the balloon. Thus, the strip in theexpanded state can have a main portion having wedge dissectors 26 thatis parallel with the axis of the balloon. Angled sections can extendfrom the main portion to the hooks 161. The angled sections can form anangle when the balloon is expanded as shown, but can be flat when theballoon is deflated. In some embodiments, hinges between the sectionscan be formed with thinner sections of material.

As shown in FIG. 14A the strip can attach to the balloon without aseparate ring by use of the hooks 161. The balloon can be glued to acatheter (for example an elongated tube with one or more lumen) whichcan also secure the hook in place. FIG. 14A shows one strip forsimplicity, though it will be understood that 2, 3, 4 (FIG. 14B), 5, ormore strips could be used.

FIG. 14C shows a detail view of the hook 161 attaching to a balloon 20.As can be seen the balloon can serve as a base layer 122 of the ring anda top layer 122 is also shown. Adhesive 123 is also shown securing thetop layer 121 to the balloon. In some embodiments, the top layer 121 canbe the tube of the catheter.

FIG. 14D shows a two layer 121, 122 ring. The two-layer ring can includetwo layers of heat shrink material. As discussed for FIGS. 10-11, thering illustrated in FIG. 14D can be a multi-layer ring where the baselayer 122 is less compressible or elastic than the top layer 121 andwhere energy is added to the top layer producing a reduction in the toplayer's diameter until the top layer compresses and captures the stripsbetween the base layer 122 and the top layer 121 to produce the cage 10.

FIG. 14E illustrates another embodiment of the rings 12, 14 that securethe strips 16 on the surface of the balloon 20. As shown in callout “A,”the rings 12, 14 can be secured to the balloon 20 such that the wedgedissectors protrude through the surface of the rings 12, 14. Callout “A”includes a cut away of the ring 12, 14 in the center in order to showthe strip 16 below. The wedge dissectors can protrude through the rings12, 14 in a variety of ways. For example, the shape of the wedgedissector can cut through the material of the rings 12, 14 as the rings12, 14 are secured to the strips 16. This can form a hole 27. The rings12, 14 can also have a plurality of holes 27 pre-cut into the rings 12,14 to allow the wedge dissectors to extend through.

It can also be seen that the rings 12, 14 can be shaped to correspondwith the taper of the balloon 20. For example, cutouts 29 of material inthe rings can help a ring made of heat shrink material to shrink to theshape of the balloon.

As discussed above, each of the strips 16 can extend between one or tworings, though additional rings can be used as needed. For example,three, four, five, six, seven, eight, nine, or ten, or more rings can beused, especially with longer balloons. As one example, an angioplastyballoon 20 having a length of 300 mm can be fitted with a cage 10 havingtwo rings 12 and 14 at either end. In addition to the rings 12, 14, thecage 10 can include rings 13 or other similar controlling elements thatcan aid the strips 16 in maintaining alignment and orientation as theballoon 20 expands towards the artery wall.

As illustrated in FIG. 15A, the rings 13 can be a fraction of theoverall length of the balloon 20. Some ring 13 designs are less than oneand a half times the length of the balloon 20. In other examples, therings are between 1.0-0.5 times the balloon 20 length. More commonly thelength of the rings 13 are between 2.5 and 1.5 times the balloon 20diameter and typically between 1.5 and 0.5 times the balloon 20diameter. Each ring 12, 13, 14 can be made from a different material soat to provide more than one advantage and function of the rings 12, 13,14.

The rings 13 can be placed on the outer surface of the body of theballoon 20. In some examples, the rings 13 can be designed to retain thebody of the strips 16 such that the position and orientation of thestrips 16 are maintained. It can also be seen, that the strip 16 doesnot extend along the shoulders of the balloon. Thus, the strip can beelongated and can extend parallel with the axis of the balloon. FIG. 15Ashows one strip 16 for simplicity, though it will be understood that 2,3, 4, 5, or more strips could be used.

These rings 13 can be positioned over the expanded balloon 20 area andmay have different properties than the rings 12, 14 on either end of theballoon 20. As illustrated in FIG. 15A, in some embodiments, the rings13 positioned over the balloon 20 surface may be more elastic inproperty than those located on the ends of the balloon 20. This canallow the rings to accommodate the expansion and refolding of theballoon 20. In some examples, the rings used on the outer diameter ofthe balloon 20 are placed over the two ends of each separated strip. Thestrips 16 may also be glued, welded, restrained by friction fit, orotherwise attached to any of the rings described above.

In some embodiments, rows of strips and/or strip segments can be placedaround the balloon 20. Some rows may extend over the entire length ofthe balloon 20 and other rows may not. In some examples, a row mayinclude a plurality of strips in series that are separated by gaps.Placing strips in a series on the balloon can provide greaterflexibility which can improve deliverability through tortuous anatomy.

As described previously, rings 12, 14, 13 can be used to retain thestrip on the surface of the balloon 20. The rings can be connected tothe strips in any number of different ways, as described in the variousembodiments herein. In some embodiments, the ends of the strips 16 withno wedge dissectors can be used to attach to the rings. In otherembodiments, the ends with wedge dissectors can attach to the rings.

FIG. 15B illustrates another embodiment of balloon catheter. A balloon20 is shown with a cage 10 with four equally spaced rows of strips 16.Each row has two strips 16 that are laid in series. A ring 13 attachesthe adjacent strips 16 to properly secure and orient the strips 16across the surface of the balloon 20. Rings 12, 14 hold down the otherends of the strips.

The callout “A” provides an enlarged view of the distal end of theballoon 20 with cage 10. The hatching illustrated in callout “A” isprovided to help visualize and delineate the different parts of thedevice. As shown, the end of the balloon 20 includes a ring 12 thatsecures a plurality of strips 16 to the surface of the balloon 20. Theballoon 20 is disposed about a catheter 19. The ring 12 can be a heatshrink material. A wedge dissector is also shown extending through thering. The placement of the strips is further clarified in FIG. 15C whichshows how a pair of strips 16 which are laid in series such that thestrips 16 span the length of the balloon 20.

To improve flexibility, the cage 10 can have rows that are made up of agreater number of strips 16 than illustrated in FIGS. 15B and 15C. FIGS.15D-15E illustrate an example where five strips 16 are laid across thesurface of the balloon 20 in series. As noted previously, each of thesestrips 16 can be secured on the surface of the balloon 20 by a pluralityof rings 13. Callout “A” provides a cut away of the ring 13 to show thegap between the two strips 16 that are in series. As described abovewith reference to FIG. 14E, the wedge dissector can protrude through thering 13 in a variety of ways. For example, the shape of the wedgedissector can cause the wedge dissector to poke through the material ofthe ring 13. As well, the ring 13 can have a plurality of holes cut intothe rings 13 to allow the wedge dissectors to poke through.

In addition to having multiple strips in rows, the gap between thestrips in a row can also be adjusted to increase flexibility. To easemanufacturing the linear alignment in the theta direction around theradius (angle drift) and the spacing alignment between the strips 16(gap) can have a relatively broad tolerance creating greater options indeveloping the manufacturing process and choosing tools. In some cases,the gap tolerance can be ±5 mm and the angle drift ±25 degrees; ±3 mmand the angle drift ±10 degrees; and ±2 mm and the angle drift ±5degrees. Cage designs that require greater tortuosity can utilize theperiodic strip placements in a linear sequence with spaced apart strips.This can enable the balloon to manage bends and turns in anatomicalspaces with less stress on the strips and more effective pushability ofthe entire system.

As shown herein many of the strips 16 have a flat bottom. This can helpthe strips 16 sit on the surface of the balloon and to maintain theorientation of the wedge dissectors. This can prevent rotationalmovement of the strips 16 on the surface of the balloon 20.

Three unique features that all strip and ring configurations can work toachieve are 1) perpendicularity of the wedge dissectors to the balloonsurface, 2) maintaining flat and low profile of the strips on theballoon, aiding in limiting the wedge dissectors from damaging tissue onits journey, and 3) either assisting in deflation of the balloon orproducing a minimal burden on the typical balloon deflationcharacteristics. To achieve these features strips typically have a flatbottom, are bounding to the balloon with rings on either end of thestrip, are folded to limit wedge dissector interaction with tissue onits journey, and when a ring lays over the wedge dissectors the wedgedissectors poke through the rings and the majority of the wedgedissector height is still available for penetration into the vessel.Although some designs utilize rings to produce forces on the balloonenabling more effective balloon deflation by either pulling on thestrips end to end or by applying radial compression, in most designs therings can support the strips by limiting strip movement, aiding in wedgedissector orientation, and preventing the strips from separating fromthe balloon. Design features that contribute to these functionalcharacteristics include: strips that have flat bottoms enabling stableorientation of the wedge dissectors but are thin enough to be laid downtangential to the balloon or contained in a fold of the balloon duringfolding, spacing between the wedge dissectors does not have a cuttingedge enabling rings to lay in the spacing and support strip retention,and the ends of the strips can be thinnest with no wedge dissectorsenabling greater surface area for rings to bond to the strip andenabling the strip to be most flexible at the edge of the balloon whereforces are highest during catheter migration to and from site ofdeployment. It will be understood that other benefits and advantages canalso be provided.

The rings 12, 13, 14 can be attached to the strips 16 in a variety ofways. FIGS. 16A-C shows examples of the rings 12, 13, 14 secured to thestrips 16. FIG. 16A shows a material wrapped around the balloon to formrings 12, 13, 14 such that the material of the ring can be secured tomore than one strip. In some examples, as illustrated in FIG. 16B, thering 12, 13, 14 can be wrapped about a portion of each strip. This canbe accomplished in the same way as illustrated in FIG. 10, where each ofthe rings can have an upper layer and bottom layer that wraps around aportion of the strip 16. FIG. 16C illustrates a solid ring 12, 13, 14that can be attached to a portion of the balloon. A portion of the stripcan be secured to the ring.

As discussed herein, many of the embodiments can use a heat shrinkmaterial for part of, or the entire ring 12, 13, 14. Heat shrinkmaterial generally starts from an extruded tube that is cross-linkedusing a form of radiation. The tube can be stretched or otherwise formedto the desired thickness. For example, it can be stretched to a flexiblemicroscopically-thin-wall tubing, it can be made rigid from a heavy-walltubing, or it can be somewhere in-between. Cross-linking can create adiameter memory and can be designed with a shrink ratio from 2:1 up to10:1. Heat shrink typically shrinks only in the radial direction but canalso shrink in length.

Heat shrink material can be manufactured from a thermoplastic material,such as polyolefin, fluoropolymer (including fluorinatedethylene-propylene (FEP), polytetrafluoroethylene (PTFE) orpolyvinylidene fluoride (PVDF)(e.g. KYNAR)), polyvinyl chloride (PVC),neoprene, silicone, elastomer or synthetic rubber and fluoropolymerelastomer (e.g. VITON). When a flexible material is desired, such as onethat expands with a balloon, the heat shrink material can include one ormore of polyolefin, silicone, elastomer or VITON (synthetic rubber andfluoropolymer elastomer).

Heat shrink material in the form of a tube can be used to slide onto orover the strips 16. The tube can have a shrink ratio of 3:1 or higher(e.g. 3.5:1, 4:1, 4.5:1, 5:1, 6:1) and allow for gentle heat shrinkingto prevent any balloon deformation or other changing of the balloon'sproperties. The material can be flexible enough to conform to theballoon through a range of balloon diameters (such as typical withsemi-compliant balloon technology ˜0.5 mm diameter range), and may havean adhesive or other coating to support the bonding of the heat shrinkmaterial and balloon. The heat shrink material can be a thin film. Theheat shrink material may also be in the form of a sheet or multiplesheets instead of a tube.

A method of retrofitting a balloon catheter with a cage can include anyof the following steps. Positioning strips around an inflated balloon.The strips may include wedge dissectors. The strips can be positionedequally spaced around the inflated balloon. The strips can extendprimarily longitudinally. The strips may be positioned serially in rows,such as 2-6 rows, each with 2-6 strips. The strips can be attachedeither permanently or temporarily to the balloon with an adhesive. Heatshrink material can be positioned around the ends of the strips as aring. Individual rings of heat shrink material can connect to or coverends of multiple strips positioned circumferentially around the balloon.Individual rings of heat shrink material can also connect to or coverends of adjacent strips positioned serially in a row. Heat can then beapplied to shrink the heat shrink material. The balloon can be deflatedand then sterilized in preparation for use.

Turning now to FIG. 17, a schematic view is illustrated showing a detailof a cage 10. In some embodiments, the strip 16 is shown having asection 34 composed of a spring zone. The spring section of the strip 16can provide a plurality of benefits. For example, the spring section 34can increase the flexibility of the cage 10. Increasing the flexibilityof the cage 10 can allow the cage 10 to more easily pass through thetortuous geometry of a blood vessel. The spring section 34 can alsoprovide a wider base for the wedge dissectors 26, to help the wedgedissectors 26 remain in the desired orientation.

In some embodiments, the spring section 34 can interface with a surfaceof the balloon 20. The spring section can help the strip 16 to remain inthe correct position with the wedge dissectors 26 in an outwardlyprojecting orientation. In some examples, the spring section cancounteract a sideways bending moment on the spike such that the wedgedissectors 26 do not bend, flex, or change position an undesirableamount. In some embodiments, the spring section 34 can also provide thebenefit of assisting the balloon 20 in refolding post inflation. Thespring can add mechanical tension on the balloon 20 to return it to acompressed state and further aid the rings in compressing the balloon 20during deflation cycles.

The spring section 34 can have an undulating configuration and beconnected to a straight section 36. In some examples, the wedgedissectors 26 can be located on the straight section. In otherembodiments, the spring section can be sinusoidal. As illustrated inFIG. 18, the spring section is shown having a larger amplitude at theproximal end as compared to the distal end. The amplitude can decreasewhile the period increases along the spring section towards the straightsection in a distal direction. In some embodiments, one side of thespring section can have a larger amplitude than the opposite side. Insome embodiments, the spring section can be symmetrical.

FIG. 18 illustrates various embodiments of the cage 10 utilizing thespring section 34 and straight section 36. Any number of differentpatterns can be used. FIG. 19 shows a detail of wedge dissectors 26 onstraight sections 36.

Although this invention has been disclosed in the context of certainpreferred embodiments and examples, it will be understood by thoseskilled in the art that the present invention extends beyond thespecifically disclosed embodiments to other alternative embodimentsand/or uses of the invention and obvious modifications and equivalentsthereof. In addition, while a number of variations of the invention havebeen shown and described in detail, other modifications, which arewithin the scope of this invention, will be readily apparent to those ofskill in the art based upon this disclosure. It is also contemplatedthat various combinations or sub-combinations of the specific featuresand aspects of the embodiments may be made and still fall within thescope of the invention. Accordingly, it should be understood thatvarious features and aspects of the disclosed embodiments can becombined with or substituted for one another in order to form varyingmodes of the disclosed invention. Thus, it is intended that the scope ofthe present invention herein disclosed should not be limited by theparticular disclosed embodiments described above, but should bedetermined only by a fair reading of the claims that follow.

Similarly, this method of disclosure, is not to be interpreted asreflecting an intention that any claim require more features than areexpressly recited in that claim. Rather, as the following claimsreflect, inventive aspects lie in a combination of fewer than allfeatures of any single foregoing disclosed embodiment. Thus, the claimsfollowing the Detailed Description are hereby expressly incorporatedinto this Detailed Description, with each claim standing on its own as aseparate embodiment.

1. (canceled) 2-55. (canceled)
 56. A balloon catheter comprising: anelongate member having an inner lumen, the elongate member defining alongitudinal axis; a balloon connected to the elongate member at adistal end of the elongate member; a cage for positioning about theballoon comprising: at least one strip comprising a plurality of wedgedissectors spaced apart along a surface of the at least one strip byopen spaces between adjacent wedge dissectors on the at least one stripsuch that a height of the adjacent wedge dissectors is greater than aheight of the open spaces in between adjacent wedge dissectors, aplurality of rings configured to secure the at least one strip to theballoon catheter, wherein the at least one strip has a first ring of theplurality of rings at a distal end, a second ring of the plurality ofrings at a proximal end, and at least a portion of the at least onestrip between the distal and proximal ends remaining uncovered by and/orunconnected to any ring, wherein the balloon and cage are configured tohave an initial state and an expanded state, wherein each ring of theplurality of rings comprise a central aperture and a plurality of holesoffset from the central aperture and comprising a narrowed portion and awider portion, wherein the wider portion is configured to accommodateeach wedge dissector, and the narrowed portion is configured toaccommodate each open space between wedge dissectors.
 57. The ballooncatheter of claim 56, wherein at least some of the rings of theplurality of rings comprise a heat shrink material.
 58. The ballooncatheter of claim 56, wherein the heat shrink material comprises one ormore of polyolefin, silicone, elastomer or synthetic rubber andfluoropolymer elastomer.
 59. The balloon catheter of claim 56, whereinthe plurality of rings secure the plurality of strips to distal andproximal ends of the balloon.
 60. The balloon catheter of claim 56,wherein the at least one strip is secured with rings at intermediatepoints of the balloon.
 61. The balloon catheter of claim 56, wherein theat least one strip extends longitudinally in a helical pattern acrossthe balloon.
 62. The balloon catheter of claim 56, wherein at least someof the rings of the plurality of rings comprise a part ring having a toplayer of heat sink material and a bottom layer of heat sink material, anend of the at least one strip sandwiched between the top layer and thebottom layer.
 63. The balloon catheter of claim 56, wherein a one end ofthe at least one strip forms a hook, and wherein the hook is disposedabout a portion of an end of the balloon.
 64. The balloon catheter ofclaim 56, wherein a portion the at least one strip has a grooved surfacewhere the strip contacts a ring of the plurality of rings.
 65. Theballoon catheter of claim 56, wherein each ring of the plurality ofrings is free-floating about the balloon.
 66. The balloon catheter ofclaim 56, wherein a portion the at least one strip includes a spring.67. The balloon catheter of claim 56, wherein the at least one strip arepositioned serially in rows around the balloon with 4 rows, each havingbetween 2-6 strips per row.
 68. A method of retrofitting a ballooncatheter with a cage comprising: positioning at least one strip aroundan inflated balloon of a balloon catheter, the at least one stripincluding a plurality of wedge dissectors spaced apart along a surfaceof the at least one strip by open spaces between adjacent wedgedissectors on the strip such that a height of the adjacent wedgedissectors is greater than a height of the open spaces in betweenadjacent wedge dissectors; advancing a plurality of rings over theballoon so that each end of the at least one strip is covered by a ring;and wherein each of the plurality of rings comprise a central apertureand a plurality of holes offset from the central aperture and comprisinga narrowed portion and a wider portion, wherein the wider portion isconfigured to accommodate each wedge dissector, and the narrowed portionis configured to accommodate each open space between wedge dissectors.69. The method of claim 70, wherein positioning the at least one stripon an inflated balloon further comprises positioning the at least onestrip to extend primarily longitudinally.
 70. The method of claim 70,where in the plurality of rings comprise of heat shrink material andheating the rings of heat shrink material to shrink the rings of heatshrink material to thereby secure the at least one strip to the balloon,at least a portion of the at least one strip between distal and proximalends of the strip remaining uncovered by and/or unconnected to any ringof heat shrink material.
 71. The method of claim 70, wherein positioningthe at least one strip on an inflated balloon further comprisespositioning the at least one strip serially in rows around the balloonwith 4 rows, each having between 2-6 strips per row.
 72. The method ofclaim 70, wherein advancing the plurality of rings over the balloonfurther comprises covering a distal end of the at least one strip with asingle ring of the plurality of rings.
 73. The method of claim 75,wherein advancing the plurality over the balloon further comprisescovering a proximal end of the at least one strip with a single ring ofthe plurality of rings.
 74. The balloon catheter of claim 56, wherein aspacing length between the wedge dissectors is from 4:1 to 3:1 space tolength.
 75. The balloon catheter of claim 56, wherein a spacing lengthbetween the wedge dissectors is from 3:1 to 1:1 space to length.